Complete conversion in generation of svg

This changes were pending on 20f18d697a2630a323f1c3a36b4fd024b6035e17
remove unneded code and fix creation of error message containers.
Unify creation of errorMsg and textMsg

Moved to a function to remove duplicated code.
Move bottom right button up to make it visible in android

Android have a bottom toolbar visible by default,
we need move the corner button up a little to avoid have it behind
the toolbar.
Unify creation of grids

Move the code to create the polar and cartesian grids to a function
Adapt buttons size to screen resolution

In the xo, the buttons are too smal to use them with touch.
Adapt the size as we do in sugar.
Merge pull request #14 from godiard/android_fixes4

Android fixes4